Automatic transmission shift control engine spark control

ABSTRACT

The engine spark timing includes an electrically actuated on-off valve in the vacuum line between the carburetor spark port and the distributor servo actuator, the valve being actuated to permit vacuum to advance the distributor only when the automatic transmission associated with the engine is conditioned for a high speed gear ratio and the intermediate speed gear ratio is disestablished; the fluid pressure actuating the intermediate and high speed ratio servos to their respective positions simultaneously actuating a pressure responsive switch in series power flow arrangement with an intermediate gear ratio servo position indicating switch to complete the circuit to the vacuum switch.

United States Patent 1191 General [4 1 Aug. 21, 1973 [75] Inventor: Norman T. General, Dearborn,

Mich.

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

221 Filed: Dec. 27, 1971 211 Appl. No.: 212,490

[56] References Cited UNITED STATES PATENTS Bale, Jr. et a1 123/117 A X 3,327,553 Peras 74/852 X 3,643,526 2/1972 Thornburgh 74/860 Primary Examiner-Arthur T. McKeon Attorney-Keith L. Zerschling et al.

[57] ABSTRACT The engine spark timing includes an electrically actuated on-off valve in the vacuum line between the carburetor spark port and the distributor servo actuator, the valve being actuated to permit vacuum to advance the distributor only when the automatic transmission associated with the engine is conditioned for a high speed gear ratio and the intermediate speed gear ratio is disestablished; the fluid pressure actuating the intermediate and high speed ratio servos to their respective positions simultaneously actuating a pressure responsive switch in series power flow arrangement with an intermediate gear ratio servo position indicating switch to complete the circuit to the vacuum switch.

6 Claims, 2 Drawing Figures AUTOMATIC TRANSMISSION SHIFT CONTROL ENGINE SPARK CONTROL This invention relates, in general, to an engine ignition timing control. More particularly, it relates to one in which advance or retard of the timing is controlled by the establishment or disestablishment of a particular gear ratio in the transmission associated with the engine.

For emission purposes, it has been found desirable to prevent advance of an engine ignition system as long as the gear ratio of the transmission associated with the engine is in a low or intermediate speed condition, and permit advance once the transmission has been conditioned for a high speed gear ratio operation.

Devices are known for controlling the operation of an engine ignition timing system in the above manner. For example, U.S. Pat No. 3,584,521, Robert S. Tooker, lgnition Timing Control, shows and describes an engine timing control of the type described. An electrically actuated valve in the vacuum line between a carburetor spark port and a distributor servo actuator is energized upon actuation of a fluid pressure actuated valve during establishment of the high speed drive in the transmission associated with the engine.

In the past, the transmission pressure actuated switch has been located in the bell housing of the transmission, which generally requires modifying the casting of the housing, which is expensive. The invention relates to an engine ignition control that provides a more economical means of sensing the gear ratio operating conditionof the transmission to provide the desired timing schedule, and one that can be adapted to existing transmissions with only minor modifications.

More particularly, it is an object of the invention to provide an engine ignition timing control of the type described that is simple to assemble and inexpensive to manufacture.

it is another object of the invention to provide an engine ignition timing control operable in response to the establishment/disestablishment of a particular gear ratio in the transmission associated with the engine to regulate the engine timing, the transmission per se requiring only slight modifications from known constructions, thereby making the engine ignition control readily adaptable to existing engine-transmission constructions.

it is a still further object of the invention to provide the above described desired regulation by replacing the intermediate speed gear ratio fluid pressure actuated servo cover with one of a slightly modified design incorporating the invention, thereby simplifying the change and reducing the expense of machining and casting, etc.. to a minimum.

it is also an object of the invention to provide an engine ignition timing control regulated by the transmisactuated by the movement of the intermediate servo piston to a release position, the switches preventing advance of the engine timing unless the transmission is conditioned for a high speed gear ratio operation.

Other objects, features and advantages of the invention will become more apparent upon reference to the succeeding detailed description thereof, and to the drawings illustrating a preferred embodiment thereof, wherein:

FIG. 1 illustrates schematically a cross-sectional view of the upper half of a multi-speed, planetary gear set type automatic transmission; and,

FIG. 2 shows schematically a cross-sectional view of a typical automatic transmission type brake band and associated servo, and an engine ignition timing control system embodying the invention.

As described previously, the invention is concerned with providing a control in the transmission associated with an engine to prevent advance of the engine timing during low and intermediate speed operations of the transmission, to reduce emissions, while permitting spark advance as soon as the transmission is conditioned for high speed operation.

The automatic transmission per se may be of many known types, one in particular, for example, being fully shown and described in U.S. Pat. No. 3,400,612, Stanley Leroy Pierce, Jr. The latter shows two interconnected planetary gear sets having friction-engaging sion associated with the engine, including a pair of brake and clutch members operated by fluid pressure actuated servos to selectively and automatically establish low, intermediate, high speed and reverse drive gear ratios. The details of construction and operation of such a transmission and its fluid pressure control system arefully shown and described in U.S. Pat. No. 3,400,6l2, and are, therefore, not repeated here, for clarity. Those details that are believed to be necessary for an understanding of the invention will be described, and any remaining details, therefore, are hereby incorporated by reference.

More specifically, the transmission shown and described in U.S. Pat. No. 3,400,612 is illustrated schematically herein in FIG. 1. It has a power input shaft 10 connected by a pair of planetary gear sets 12 and 14 to a power output shaft 16. The gear sets contain annular ring gears 18, 20, sets of circumferential spaced planet gears 22, 24 rotatably mounted on planet carriers 26, 28 and meshing with the ring gears and a common sun gear 30.

input shaft 10 is selectively connected to ring gear 18 by a fluid pressure actuated friction clutch 32 and/or to the sun gear 30 by fluid pressure actuated friction clutch 34. A plurality of brake bands 40 and 42 can be applied by fluid pressure to respectively establish intermediate gear ratio, or a low or reverse gear ratio. The first gear set carrier 26 and the second gear set ring 'gear 20 are both connected to the output shaft 16, and the second gear set carrier 28 is adapted to be held against reverse rotation by a known type of one-way brake 44.

in operation, briefly, low forward speed is established by engaging clutch 32. Clockwise rotation of input shaft 10 drives ring gear 18 in the same direction to retate planet gears 22 and attempt to rotate sun gear 30 counterclockwise. This attempts to drive the output shaft 16; the latter. however, acting temporarily as a reaction member to attempt to cause reverse or counterclockwise rotation of the planet carrier 28. This rotstion, however, is prevented by engagement of the oneway brake 44 so that the planet carrier 26 is caused to rotate in a clockwise forward direction at a slow speed. Engine overrun or driving of carrier 28. in a forward clockwise direction may be prevented by engagement of the brake band 42.

Intermediate speed operation is obtained by applying the intermediate brake band 40 to engage and hold stationary the sun gear 30, while maintaining the forward clutch 32 engaged. A drive then is obtained solelythrough the front planetary gear set with the sun gear 30 acting as a reaction member to effect a forward clockwise drive of output shaft 16 at an intermediate speed gear ratio.

High speed operation is established by engaging both clutches 34 and 32 and disengaging brake band 40. The simultaneous clockwise forward rotation of ring gear 18 and sun gear 30 locks up the gear sets and provides a direct drive from input shaft to output shaft 16. For clarity, other operations are not described since they do not play any part in the present invention.

It is to be noted that in establishing the high speed gear ratio, the intermediate brake band 40 is disengaged or released while the high speed or direct drive clutch 34 is applied. Referring now to FIG. 2, the latter figure illustrates the intermediate brake band 40 and a servo 50 for effecting engagement or disengagement of the brake band 40 with a rotating portion of the transmission. In this case, the latter would be the member 52 connecting the sun gear and the driven side of the friction disc type direct drive clutch 34.

The band 40 is shown as having a pair of anchor eyelets 54 to which are secured a pair of struts or links 56, 58. The strut 56 is adjustably mounted as shown to a stationary portion 60 of the transmission housing. The opposite strut 58 is pivotally connected to a sliding plunger 62 of servo 50.

More specifically, the transmission case or housing is provided with an enlarged portion 64 recessed at one end to provide a piston bore 66. A stepped diameter piston 68 is slidably and sealingly mounted for reciprocation in the bore and has a press fit with the plunger 62 as shown. Movement of the servo in a leftward direction as seen in FIG. 2 will cause the band 40 to engage the gear connecting member 52 (FIG. 1) to hold it stationary and thereby hold stationary sun gear 30 to establish the intermediate speed gear ratio previously described. Alternatively, movement of piston 68 in the opposite right hand direction as seen in FIG. 2 will spread the brake band 40 and disengage it from the gear connecting member 52. This will permit rotation of sun gear 30 by the drive shaft 10 upon engagement of the direct drive clutch 34, as previously described.

Piston 68 is adapted to be moved to a brake band apply position by fluid pressure admitted to a chamber 70 defined between the piston and a servo cover 72. A line 74 connects to chamber 70 through a passage 76 provided in the plunger 62. An opposite chamber 78 is adapted to be supplied with fluid under pressure through a passage 80 to offset the apply pressure in chamber 70 and permit a servo release spring 82 to stroke the piston 68 in a rightward direction.

The supply of fluid pressure selectively to opposite chambers 70 and 78 is regulated by a fluid pressure control system of a known type and preferably in this instant the same as that shown in U.S. Pat. No.

3,400,612 previously referred to above and incorporated herein by reference.

The fluid pressure that is applied through line to disengage the intermediate servo is the same fluid pressure that is used to engage the high speed direct drive clutch 34, as shown more particularly and described in U.S. Pat. No. 3,400,612. As shown in the latter patent, in FIGS. 2a, 2b and 2c, the intermediate servo 54 therein is essentially the same construction as the servo 50 shown herein in FIG. 2.

It will be seen upon consideration of the fluid pressure control system of the latter patent that establishment of intermediate speed gear ratio is provided by the flow of apply pressure from a front pump through a line 106 to the manual valve, which, when in a D-l position, directs fluid under pressure through a line 178 to a line 184 leading to the 1-2 shift valve. The latter valve, when moved to its down position by vehicle speed responsive governor pressure in a line 200, connects lines 184 and 328 to direct fluid under pressure to the I-2 shift capacity scheduling and accumulator valves. The line pressure flows past the valve 420 into the line 332 and to the 2-3 backout valve, which in the position shown, connects line 332 to line 336 leading to the apply side of the intermediate servo shown in FIG. 2b. Accordingly, the intermediate servo piston is stroked leftwardly to tighten the band around the friction transmission means, not shown, to hold the gear connecting member stationary and thereby provide intermediate speed gear ratio in the manner previously described.

Similarly, a shift to high speed or direct drive ratio occurs when the 2-3 shift valve shown in FIG. 2b of U.S. Pat. No. 3,400,612 moves downwardly. Line pressure from the front pump flows through line 106 to the manual valve where it is distributed to a line 180 leading to the down 2-3 shift valve, where it is connected to line 286. The latter line leads to the Reverse and Direct Clutch servo applying the same, and through a restricted connection 290 connects with line 288 leading to the off side of the intermediate servo chamber ('78 herein). The line 286 leading from the 2-3 shift valve branches to flow line pressure into a line 346 acting on the 2-3 backout valve shifting the same and thereby connecting line 346 to line 336. The latter line leads line pressure to the on or apply side of the intermediate servo thereby effecting a balance of line pressures between the on and off sides and permitting the spring 82 (herein) to stroke the piston 68 (herein) rightwardly. This opens or spreads the brake band 40 and releases the gear connecting member 40 to be driven by drive shaft 10 (FIG. 1 herein) through the now engaged clutch 34. This then provides the direct drive previously described.

From the above description, therefore, it will be seen that the intermediate servo 68 herein is stroked to an off position to disengage the intermediate speed gear ratio by fluid pressure at the same level that is used to engage the direct drive clutch to condition the transmission for a high speed gear ratio drive. It will be noted, therefore, that the line pressure available in direct drive or high speed drive can be sensed anywhere along the line between the direct drive clutch and intermediate servo.

Turning now to the invention, as stated previously. the known devices provide a fluid pressure actuator switch having a housing cast in the bell housing of the transmission, which is uneconomical. The invention simplifies the installation of such a switch by incorporating the switch devices into the cover 72 of the intermediate servo. Thus, it is merely necessary to replace the conventional servo cover 56 of US. Pat. No. 3,400,612 with one incorporating switches to be described.

More specifically, referring to FIG. 2 herein, the intermediate servo cover 72 is shown as incorporating a fluid pressure actuated switch 90 connected by passage 92 to the servo apply chamber 70. The switch includes a pair of contacts 94. Details of the construction of the switch are not given since they are known and believed to be unnecessary for an understanding of the invention. Suffice it to say, however, that the contacts normally would be unbridged by means of a spring, the force of which is such as to prevent bridging'of the circuit below a predetermined fluid pressure in chamber 70 corresponding to that level near or indicative of the level obtainable during direct drive or high speed gear train operation.

It should be noted that with a hydraulic circuit of the type shown and described in U.S. Pat. No. 3,400,612, and the use of a switch sensing intermediate servo apply hydraulic pressure level, during intermediate speed operation with the transmission operating essentially at stall speeds, the TV or throttle valve pressure acting on the main pressure regulator valve will be quite high, and could be equal to the line pressure level obtainable in direct drive during coasting operation, for example, when the throttle valve pressure then is essentially zero and, therefore, the line pressure at its lowest level during this particular operation.

Accordingly, it is desirable to incorporate an additional switch in the electrical circuit including the fluid pressure actuated switch 90 to prevent advance of the engine timing until the transmission is conditioned for high speed or direct drive operation.

To this end, the intermediate servo cover 72 includes a position responsive switch 96 having a movable stem 98 spring biased into the path of movement of the servo 68 in a release direction. The construction is such that when the servo 68 is stroked in a rightward release direction by fluid under pressure in line 80 and chamber 78, it engages the stem 98 and moves it rightwardly to bridge the circuit between its pair of contacts 100.

Thus, it will be seen that when the intermediate servo is stroked to apply the intermediate brake band, the position switch 96 will open upon leftward movement of the piston 68, thereby breaking the circuit, regardless of the level of fluid pressure acting on the switch 90. Also, it will be seen that when the direct drive or high speed ratio clutch is established, the rightward stroking of the servo piston 68 to disestablish the intermediate speed gear ratio will not only effect closing of switch 96 but also the fluid pressure will close switch 90 to complete a circuit between the two.

The two switches control the engine ignition timing. The latter includes a distributor 110 having a timing cam 112 and a rotatable breaker plate 114 pivotally mounted to advance or retard the ignition timing, in a known manner. The breaker plate is movable in opposite directions by a rod 116 fixed to a flexible annular diaphragm 118 in a vacuum servo 120. The latter includes a hollow shell 122 divided into an air chamber 124 and a vacuum chamber 126 by the diaphragm 118. A spring 128 normally biases the diaphragm and rod 116 to move the breaker plate 1 14 to a maximum spark retarded position.

The vacuum chamber 126 is connected by a line 130 through an on-off vacuum control valve 132 to a carburetor normally associated with the engine. More specifically, FIG. 2 shows a portion 134 of a down-draft type carburetor having the usual induction passage 136. Flow of air and fuel through the passage is controlled by a throttle valve 138 fixed to a shaft 140 rotatably mounted in the side walls of the carburetor. A vacuum or spark port 142 is provided just above the edge of the closed position of the throttle valve plate, and is connected by a line 144 to the vacuum valve 132.

The vacuum valve in this case is shown as having a direct-through connection 146 and a vent line 148 connected to atmospheric pressure at its termination 150. A block 152 is also provided. The valve is normally biased by a spring 154 to a position connecting the servo vacuum line 130 to the vent line 148 so that the servo spring 128 can normally condition the engine ignition timing for a maximum retard operation. The valve 132 is adapted to be moved to the position shown connecting the carburetor spark port vacuum to the servo to permit normal advance of the ignition timing by means of a solenoid 156 that is adapted to be energized when the two intermediate servo switches 90 and 96 are closed. More specifically, the solenoid 156 is in the line of an electrical circuit including a ground 158, and a line 159 to the two switches 90 and 96 in a series power flow arrangement with a power source, which in this case is a conventional vehicle battery 160.

In operation, so long as the transmission is conditioned for low or intermediate speed ratio, the on-off vacuum control valve 132 will be in its off position disconnecting the servo vacuum line 130 from the carburetor spark port vacuum line 144, thus conditioning the engine ignition timing for a maximum retarded operation. This is effected because in the low speed operation of the transmission, as detailed in US. Pat. No. 3,400,612, no fluid pressure exists in either chamber 70 or 78 herein in the intermediate servo 50, and the spring 82 strokes the piston 68 rightwardly to the released position. This closes the position indicator switch 96; however, with no fluid pressure in chamber 70, the switch 90 remains open and the circuit remains broken between battery 160 and solenoid 156.

In intermediate speed operation, while fluid pressure exists in chamber 70 of the intermediate servo 50, and may be of a level sufficient to actuate the pressure switch 90, the on position of the intermediate servo has stroked the piston 68 leftwardly to open switch 96 and thus again break the circuit between the battery 160 and solenoid 156.

When high speed or direct drive gear ratio is established by simultaneous flow of fluid under pressure to the direct drive clutch 34 and to both chambers 70 and 78 of the intermediate servo, as previously described, the servo piston 68 is stroked rightwardly by spring 82, thus closing the switch 96 and also closing switch 90 because of the fluid pressure level at this time. This completes the circuit between battery 160 and the solenoid 156 thereby moving the on-off vacuum valve 132 to the position shown connecting the spark port vacuum in line 144 to the servo vacuum line 130. From this point on, so long as the transmission is conditioned for high speed gear ratio, advance of the ignition timing is permitted according to the position of throttle valve 138.

It will be seen, therefore, that the invention provides a simplified control for the automatic switching of the on-off vacuum valve for controlling the engine ignition timing merely by means of modifying the cover of the intermediate servo as compared to providing a modification of the entire transmission bell housing.

While the invention has been shown in its preferred embodiment in the drawings, it will be clear to those skilled in the arts to which it pertains that many changes and modifications may be made thereto without departing from the scope of the invention.

I claim:

1. An engine ignition timing control comprising in combination, an engine timing system that is advanced and retarded as a function of the increase and decrease respectively of carburetor spark port vacuum applied thereto, and on-off valve means controlling the application of spark port vacuum as a function of the establishment or disestablishment of a particular gear ratio of a transmission that is drive connected to the engine, the transmission having a number of fluid pressure actuated servos operable to establish low, intermediate and high speed gear ratios, and first and second means responsive to the establishment of one speed gear ratio and the disestablishment of a second gear ratio to effect actuation of the valve means to an on position, and including a first fluid pressure actuated means actuated in response to the one gear ratio servo apply line pressure applied thereto, and second position actuated means actuated in response to movement of the second gear ratio establishing and disestablishing servo to a position disestablishing the second gear ratio, and means connecting the first and second means in a series power flow relationship to the valve means.

2. An engine timing as in claim 1, the first and second means being responsive to the establishment of a high speed gear ratio and the disestablishment of the intermediate speed gear ratio to actuate the on-off valve means.

3. An engine timing control as in claim 2, the intermediate gear ratio servo including a piston movable in opposite directions by fluid pressure applied thereto to apply or disengage respectively a gear engaging member, spring means biasing the servo towards a disengaged position, the position actuated means being engaged and actuated by the piston upon movement thereof to the disengaged position.

4. A timing control as in claim 3, the fluid pressure actuated switch being actuated by the same fluid pressure actuating the high gear ratio servo.

5. An engine timing control as in claim 3, the on-off valve means being electrically actuated to an on position in response to concurrent actuation of the fluid pressure and position actuated means, the latter including a pair of switches in series flow circuit arrangement with the on-off valve means.

6. An engine ignition timing regulator controlled to advance or retard the timing as a function of the establishment/disestablishment of a particular gear ratio of a transmission that is drive connected to the engine, the transmission having a plurality of interconnected planetary gear sets each having drive, driven and reaction members, brake and clutch friction engaging means operatively engagable with selective ones of said members at times to alternately establish low, intermediate and high speed gear ratios, fluid pressure actuated servo means operatively engagable with the brake and clutch means for actuating the same and including first intermediate and second high speed gear ratio establishingldisestablishing servos, the servos being biased to a gear ratio disengaged position, the first intermediate servo having piston means movable in a friction means engaging direction by fluid pressure to .establish intermediate gear speed ratio and movable in the opposite direction to disengage the intermediate speed gear ratio by fluid pressure simultaneously moving the second high speed servo to effect establishment of the high speed gear ratio, movable means to adjust the engine timing, a third vacuum controlled servo having a plunger operatively connected to the movable means and movable by spring means therein to a position retarding the ignition timing and movable by vacuum connected thereto from a carburetor induction passage port located above the closed position of a throttle valve therein to advance the ignition timing as a function of the movement of the throttle valve, a normally closed open-closed valve in the connection between the carburetor vacuum port and the third servo controlling vacuum flow therebetween, and electrically controlled means to actuate the valve to an open position, an electrical circuit including a first fluid pressure actuated switch and a second servo piston position switch arranged in a series power flow in the second servo, the first switch being moved to bridge the circuit by the attainment of a predetermined level of the servo apply fluid pressure applied thereagainst, the second switch being actuated to bridge the circuit by movement of the second servo piston thereagainst upon movement of the latter piston in the opposite intermediate gear speed ratio disestablishing direction. 

1. An engine ignition timing control comprising in combination, an engine timing system that is advanced and retarded as a function of the increase and decrease respectively of carburetor spark port vacuum applied thereto, and on-off valve means controlling the application of spark port vacuum as a function of the establishment or disestablishment of a particular gear ratio of a transmission that is drive connected to the engine, the transmission having a number of fluid pressure actuated servos operable to establish low, intermediate and high speed gear ratios, and first and second means responsive to the establishment of one speed gear ratio and the disestablishment of a second gear ratio to effect actuation of the valve means to an on position, and including a first fluid pressure actuated means actuated in response to the one gear ratio servo apply line pressure applied thereto, and second position actuated means actuated in response to movement of the second gear ratio establishing and disestablishing servo to a position disestablishing the second gear ratio, and means connecting the first and second means in a series power flow relationship to the valve means.
 2. An engine timing as in claim 1, the first and second means being responsive to the establishment of a hIgh speed gear ratio and the disestablishment of the intermediate speed gear ratio to actuate the on-off valve means.
 3. An engine timing control as in claim 2, the intermediate gear ratio servo including a piston movable in opposite directions by fluid pressure applied thereto to apply or disengage respectively a gear engaging member, spring means biasing the servo towards a disengaged position, the position actuated means being engaged and actuated by the piston upon movement thereof to the disengaged position.
 4. A timing control as in claim 3, the fluid pressure actuated switch being actuated by the same fluid pressure actuating the high gear ratio servo.
 5. An engine timing control as in claim 3, the on-off valve means being electrically actuated to an on position in response to concurrent actuation of the fluid pressure and position actuated means, the latter including a pair of switches in series flow circuit arrangement with the on-off valve means.
 6. An engine ignition timing regulator controlled to advance or retard the timing as a function of the establishment/disestablishment of a particular gear ratio of a transmission that is drive connected to the engine, the transmission having a plurality of interconnected planetary gear sets each having drive, driven and reaction members, brake and clutch friction engaging means operatively engagable with selective ones of said members at times to alternately establish low, intermediate and high speed gear ratios, fluid pressure actuated servo means operatively engagable with the brake and clutch means for actuating the same and including first intermediate and second high speed gear ratio establishing/disestablishing servos, the servos being biased to a gear ratio disengaged position, the first intermediate servo having piston means movable in a friction means engaging direction by fluid pressure to establish intermediate gear speed ratio and movable in the opposite direction to disengage the intermediate speed gear ratio by fluid pressure simultaneously moving the second high speed servo to effect establishment of the high speed gear ratio, movable means to adjust the engine timing, a third vacuum controlled servo having a plunger operatively connected to the movable means and movable by spring means therein to a position retarding the ignition timing and movable by vacuum connected thereto from a carburetor induction passage port located above the closed position of a throttle valve therein to advance the ignition timing as a function of the movement of the throttle valve, a normally closed open-closed valve in the connection between the carburetor vacuum port and the third servo controlling vacuum flow therebetween, and electrically controlled means to actuate the valve to an open position, an electrical circuit including a first fluid pressure actuated switch and a second servo piston position switch arranged in a series power flow in the second servo, the first switch being moved to bridge the circuit by the attainment of a predetermined level of the servo apply fluid pressure applied thereagainst, the second switch being actuated to bridge the circuit by movement of the second servo piston thereagainst upon movement of the latter piston in the opposite intermediate gear speed ratio disestablishing direction. 